[EDITOR EXTENSION] ParrelSync: Test multiplayer without building(uEcho replacement)

ParrelSync is a Unity editor extension that allows users to test multiplayer gameplay without building the project by having multiple editor windows opened and mirrored the changes from the original project.

We've been using this for months since uEcho isn’t working with Unity 2019 anymore, and I feel it is safe to share it as a replacement now. Please don’t hesitate to let us know if you have encountered any problem or want any new feature to be added :)

Test project changes on clients and server within seconds - both in editor

GitHub Home Page: https://github.com/VeriorPies/ParrelSync


  • Test multiplayer gameplay without building the project
  • GUI tools for managing all project clones
  • Protected assets from being modified by other clone instances
  • Handy APIs to speed up testing workflows


  • Backup your project folder or use a version control system such as Git or SVN

  • Download .unitypackage from the latest release and import it to your project.

  • Parrel Sync should appreared in the menu item bar after imported

Check out the Installation-and-Update page for more details.

Supported Platform
Currently, ParrelSync only supports Windows editor.

Please create a feature request if you want Mac/Linux support to be added.

ParrelSync has been tested with the following Unity version. However, it should also work with other versions as well.

  • 2019.3.0f6

  • 2018.4.22f1

There's some useful APIs for speeding up the multiplayer testing workflow. Here's a basic example:

if (ClonesManager.IsClone()) {

  // Automatically connect to local host if this is the clone editor


  // Automatically start server if this is the original editor


Check out the doc to view the complete API list.

Discord Server
We have a Discord server.

Need Help?
Some common questions and troubleshooting can be found under the Troubleshooting & FAQs page.

You can also create a question post, comment under the Unity forum thread, or ask on Discord if you prefer to have a real-time conversation.


Long time Unity user, first time poster, just to say thank you for this extension. I've been working in Mirror multiplayer for months without a solution such as this, and it's desperately needed. Thank you again!


This needs way higher visibility. Build times with il2cpp are prohibitive so you really need these assets.

Is it possible to have the same layers in the original project and the clone ? I'm having trouble with that.

Thank you because this is saving me a lot of time :)

I found this because of a youtube series by "Shrine_Wars"
Thank you for making this! It's incredible.

1 Like

Extremely usefull addon, thanks for my saved times

<3 <3 <3 <3

Hi I have a question, can I alternately control the two instance of the parrelsync, for example I want to control player one then after that control player two. something like that

does NOT work in 2021.3.4 for me. Sigh. Keeps telling me "unity parrelsync asset modifications saving detected and blocked". Everything is pink and all my vfx graphs are lying, telling me they don't see variables that are clearly there. I'm not going to pretend-fix these references one by one. I disabled edit > preferences > asset pipeline > directory monitoring and there was no difference from when it was true. Just very annoyed with game design at this point. I'm on an LTS version and have a broken project thanks to it. Just overly frustrating.

Why didn't you make a backup?


How come this never made it to the Unity Asset Store?

1 Like

I can't sign in with different firebase user accounts on clones, firebase is remembering the authentication somewhere, which is not cloned

I can't thank you enought. Without you, multiplayer game development would be 100000 times harder. Thank you!

I am having the same issue

Hiya. Quite interested in making use of this as it'd be a huge time saver, but for whatever reason my cloned project won't "Open In New Editor". Instead it brings up Unity Hub which flashes and does nothing. Trying to add the cloned project directly to the Hub results in an invalid project error. How can I work around the screwy Hub? Thanks!

1 Like

Im having the same issue have you found any solutions yet?

UPDATE: I have figured it out for anyone who may be struggling with this same issue. In my case, i had my game on an external drive, so i moved both the clone and the game over to a new folder i created and started it up and it didn't seem to do much, but then I deleted the old clone and made a new one and it works suddenly.

Not sure what was wrong with the old clone but I hope this saves someone hours of agonizing stress and headaches as it caused for me lol